The present invention relates to an image forming apparatus which forms a toner image on the image carrying member by electrophotography and transfers it onto a transfer material to obtain an image, and more particularly, to an image forming apparatus such as a printer, a copier or a facsimile provided with a process cartridge integrated with an image carrying member and at least one of a developing means and a cleaning means.
With the current reduction of size and weight and heightened performance of image forming apparatus such as printers and copiers, image forming apparatus have been loaded with a greater density and have become more complicated. On the other hand, for the ordinary user, that is, operator it has become easier to perform maintenance and management with an image forming apparatus having a process cartridge integrating the image carrying member with at least one of a developing means and cleaning means.
This image forming apparatus having the process cartridge, such as the printer and copier, allows an operator having no specialized knowledge to perform maintenance and management of the image forming apparatus by replacing the process cartridge when the image carrying member in the process cartridge deteriorates. For the purpose, a guide member is provided for the process cartridge in the main body, and an operator can load the process cartridge so as to obtain optimum images by inserting the process cartridge along this guide member. In conventional apparatus, the insertion direction of a process cartridge is perpendicular to the loading direction of a transfer material in this case, so that the process cartridge handling direction differs from the transfer material handling direction.
Therefore, this makes these works troublesome, space for the installation of an image forming apparatus is restricted and a large working space is required for maintenance.
To solve these disadvantages, Japanese Patent laid open No. 61-279870 was proposed. The proposed image forming apparatus is able to facilitate the handling and operation of consumable and reduce the restriction on working space by making the loading direction of the transfer material the same as the loading direction of the process cartridge mounted on the upper case.
However, in the image forming apparatus disclosed in this Japanese Patent laid open No. 61-279870, upon the replacement of the process cartridge, an operator must open the upper case, and pull and take off the process cartridge from the upper case. For this reason, the work is not only very troublesome but also the operator must use considerable force if the process cartridge is heavy or large. Further, when a paper jam occurs, he must put his hand into the narrow section to remove the transfer material. Even if the upper case is open, a sufficient working space cannot be secured, so that jam clearance work is very hard. Additionally, the operator may sometimes touch a section stained with toner or the image carrying member directly. Even if the process cartridge is moved or removed to secure a sufficient working space, the operator also must pull out the process cartridge from the upper case and this work is troublesome for him so that jam clearance is still difficult to do.
In addition, the present invention relates to an image forming apparatus which forms images on a transfer material of copiers and printers by electrophotography, and more particularly, to an image forming apparatus to which each process material including the image carrying member for image forming is loaded or unloaded in one unit. Various methods and devices have been proposed to obtain color images by electrophotography. For example, the method disclosed in Japanese Patent laid open No. 61-100770 obtains color copies by forming latent images on the photoreceptor, which is an image carrying member, depending upon the number of separated colors, developing, transferring each developed image onto a transfer drum to form a multi-color image and then transferring the image onto a transfer material.
The device based on this method needs a transfer drum large enough to allowing an image to be transferred onto the surface, in addition to a photoreceptor drum, so that the device cannot help but become larger and complicated.
There is another method according to which a latent image is formed on the photoreceptor drum depending on the number of separated colors, each image is developed and transferred onto a transfer material to obtain a multi-color color copy, as disclosed in Japanese Patent laid open No.61-149972. This method cannot provide a good quality color copy because it is difficult to registrate one image upon another image for a multiple color image. Additionally, there is another method according to which a latent image is formed on the photoreceptor drum depending on the number of separated colors, and each color is registrated on the photoreceptor drum for a multiple color toner image, and then transferred. The basic process of this multi-color image forming is disclosed in Japanese Patent laid open Nos. 60-75850, 60-76766, 60-95456, 60-95458 and 60-158475.
These multi-color image forming apparatus which obtain a color image by registrating one image over another are equipped with multiple developing devices containing different color toners around the photoreceptor drum and generally the photoreceptor drum is rotated multiple times to develop a latent image on the photoreceptor drum and obtain a color image.
In case of a color image forming apparatus, in particular, the image forming apparatus provided with multiple developing devices and corresponding toner supply units, the structure of the image forming section is complicated thereby making it very difficult to conduct the inspection, maintenance and replacement or replenishment of each process material.
For this reason, a structure is applied in which the photoreceptor and cleaning device or photoreceptor, developing device and cleaning device are integrated into a cartridge, mounted to the main body as a unit, and the cartridge can be removed from the main body easily when required.
However, when loading the cartridge on the main body, it is necessary to place each process material at its specified position and ensure a complete connection between the main body and drive system.
The device having a toner supply unit in the main body needs to be structured so that the supply pipe can be automatically connected and disconnected depending on the attachment and detachment of the cartridge and also a procedure to prevent toner from scattering into the main body is required.